Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Setting up NAT/WAN for the first time (1841)

Hello.

Having recently bought a Cisco 1841 and learning how to set things up by the minute I'm now at the point of understanding how NAT works.

I've set up Interface FastEthernet0/0 on the router with ip 10.10.10.1, sub mask 255.255.255.248. It's also acting as a DHCP server.

My wish is for the clients on the LAN to have access to Internet. Currently sitting in SDM on a PC looking at Configure/NAT/Create NAT Configuration and the "Basic NAT" seems like a good idea but it requires me to have two router interfaces configured. I assume the other interface should be the WAN one on the router? I have a static IP from our ISP along with dns, gateway and such but I can't find where to input this data in SDM.

Any advice is greatly appreciated. Please take note that I am a novice in networking so most of your information will be new (and very helpful) to me.

2 REPLIES
Hall of Fame Super Blue

Re: Setting up NAT/WAN for the first time (1841)

Craig

Sorry but i haven't used SDM but from the command line you would do the following. For this example fa0/1 is your WAN Interface -

int fa0/1

ip address 195.17.10.2 255.255.255.248 <-- this is IP from your ISP

ip nat outside

int fa0/0

ip nat inside

ip route 0.0.0.0 0.0.0.0 195.17.10.1 <-- this default-gateway supplied by ISP

access-list 101 permit ip 10.10.10.0 0.0.0.255 any

ip nat inside source list 101 interface fa0/1 overload

You will need to add the DNS server that the ISP gave you into your DHCP config on the router.

Jon

New Member

Re: Setting up NAT/WAN for the first time (1841)

Thanks alot for your reply Jon, I'll be doing this on Monday and see how it turns out.

Quick questions,

1. How do I find out the name of my WAN interface port? It's labeled CTRLR T1/E1 0 on the actual router (1841). I assume you can't use the FE0/1 port as a WAN port.

2. In your example, what exactly is the int fa0/0? My guess would be that it's short for interface fastethernet0/0 (which is my current LAN port)?

Since I'm new with Cisco stuff, SDM helps a bit more initially, not that I mind doing it through the command line but there's so much syntax I yet have to learn.

Thanks again.

475
Views
0
Helpful
2
Replies